The objective of the research study was to analyze the effect of temperature while baking crispy buttery cookies on the formation of some selected furan derivatives, such as 5-hydroxy-2-metylofurfural (HMF), furfuryl alcohol (F_ol), and aldehyde (F_al). Shortbread-biscuits were baked under the laboratory conditions at a temperature of 200, 215, 230, and 245 °C. The changes in temperatures were monitored using a fibre optic sensor situated in the core of the cake. The baked cookies were analyzed for their antioxidant capacity. It was found that the formation of furan derivatives in cookies depended on the time and temperature of baking, and the biggest accumulation of those compounds occurred after water was evaporated and, as a result thereof, a sudden increase in the temperature inside the product occurred. The concentration of F_al in the product analyzed increased to ca. 160 mg/kg with the increase in the baking temperature to 245 °C, whereas, under the same conditions, the concentration of F_ol did not exceed 40 mg/kg. Regardless of the baking temperature, HMF was the major part of furan derivatives formed, and its maximum concentration in the analyzed material was more than 4.5 ×10³ mg/kg. A longer baking time results in the increase in antioxidant capacity of the product due to the formation of Maillard products.